Series numeration from GoodReads.

Laurie Moran and her fiance, Alex Buckley, are just days away from their midsummer wedding when Alex's seven-year-old nephew, Johnny, vanishes from the beach. Witnesses recall Johnny playing in the water and collecting shells near an ice cream shack, but when his new sitter turned her head, he had vanished. As the sun sets, Johnny's skim board washes up to shore, and everyone realizes that he could be anywhere, even in the ocean. Could the abduction be related to the wedding? Was Laurie's ten-year-old son the intended target? Or was Johnny abducted by a stranger? Laurie and Alex, along with Johnny's parents and Leo Farley, Laurie's father and a retired NYPD detective are determined to track down every lead.... -- from book jacket.